Expansible sheave



June 19, 1934. wHlTTEN ET AL 1,963,816

EXPANS IBLE SHEAVE Filed Feb. 9, 1933 2 Sheets-Sheet l ALL-WkiZZen film/70312169 June 19, 1934.

N. L. WHITTEN El AL 1,963,816

EXPANSIBLE SHEAVE Filed Feb. 9, 1933 2 Sheets-Sheet 2 I- n l fin lV-L-hlk illerz am/ 70.94

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Patented June 19, 1934 UNITED STATES meas es PATNT OFFHE EXPANSIBLE SHEAVE Application February 9, 1933, Serial No. 656,004

2 Claims.

This invention relates to sheaves or pulleys and more particularly to an expansible and contractible pulley or sheave.

An object of this invention is to provide a sheave wherein the diameter may be varied so as to provide varying degrees of speed for either a drive or driven shaft.

Another object of this invention is to provide a sheave which may be varied in diameter without stopping the rotation of the sheave or driving means.

A further object of this invention is to provide a sheave of this kind which is exceedingly simple in construction so that it will embody a relatively small number of parts and thereby permit the application of the sheave to any con ventional shaft either drive shaft or driven shaft.

The above and various other objects and advantages of this invention will in part be described and in part be understood from the following detailed description of the present preferred embodiment, the same being illustrated in the accompanying drawings wherein:

Figure 1 is a longitudinal section partly in de- 55 tail of a sheave constructed according to the preferred embodiment of this invention.

Figure 2 is a detail front elevation of the sheave mounted on a shaft.

Figure 3 is a side elevation of the hub partly in section which is mounted on a shaft, the shaft being partly broken away.

Referring to the drawings wherein like characters of reference designate corresponding parts throughout the views, the letter P designates a power member in the form of a motor having a shaft S to which is adapted to be connected suitable driven elements. This shaft S is shown diagrammatically and may be either a drive shaft connected to a power member of any suitable type or may be a driven shaft.

In order to provide a means whereby the speed of the driven elements may be varied, I have provided a variable diameter sheave, which comprises an outer hub element 10 and an inner hub element 11, which are secured as by a key 12 to the shaft S. The hub element 10 is secured against longitudinal movement relative to the shaft S by means of a set screw 13 or the like, and a set screw 14 extends through the hub 11 and holds this hub 11 against longitudinal movement on the shaft S.

A plate 15 is formed with the hub 10 and in like manner, a plate 16 is formed with the hub 11, and these two plates 15 and 16 are spaced apart and connected by means of a plurality of pins 17. The plates 15 and 16 are provided with alined radially arranged slots 18 and slide members 19 having ribs 20 engaging in the slots 18 are loosely disposed between the two plates 15 and 16.

These slide members 19 are of substantially V-shaped construction with the apex disposed innermost, and a rim or sheave member 21 of segmental type is secured to each slide member19. The rim members 21 are adapted to extend beyond the opposite edges of the slide members 19 so that when the slide members 19 are positioned in innermost position, the confronting edges of the segmental sheave members 21 will substantially contact one with another.

The outer or peripheral surface of the segmental members 21 may be formed in any desired configuration but, in the present instance, are provided with a plurality of V-shaped grooves 22 to receive a plurality of V-shaped belts or the like. However, we do not wish to be limited to 7 this particular type of peripheral surface construction as the surface of the segmental members may be varied to suit the various types of belts which are adapted to be operated about the shaft S.

Each slide member 19 is provided with an inclined passage 23 through which a bar 24 is slidably disposed and this bar 24 constitutes a part of an operating means whereby the segmental members 21 are expanded or contracted as may be desired. The bars 24 in the present instance, are inclined outwardly in a converging relation toward the shaft S, and the outer ends of the bars 24 are secured in a plate 25, which is splined ont a shaft extension 26. i i

The plate 25 is adapted to rotate with the shaft S but to have longitudinal movement on the shaft extension 26. A second plate 27 having a hub 28 is also splined on the shaft S on the side of the sheave opposite from the plate 25, and the bars 24 have the opposite or divergent ends thereof fixedly secured to the plate 27. The p1ate'27 with the hub 28 is adapted to have longitudinal sliding movement on the shaft S but is rotatable therewith and is keyed on the shaft S by means of the key 12. The plate 25, in the present instance, is held against rotation relative'to the shaft extension 26 by means of a key 29, but is permitted to have longitudinal sliding movement on this shaft extension.

A sleeve 30 is disposed about the shaft S and is provided with an arm 31 having an aperture 32 in which a stop pin or member 33 is positioned, the stop pin 33 being secured to the housing of the power member P or to any other fixed element so that the sleeve will be held against rotation relative to the shaft S.

An outer ring or anti-friction element 34 is disposed within the interior of the sleeve 39 and is preferably fixed relative to the sleeve 30 which in turn is held against rotation. A second anti-friction element 35 is secured to the shaft S, and pairs of anti-friction members 36 in the form of ball bearings, are interposed between the ring members 34 and 35, and the anti-friction means in the form of the two ring members 34 and 35 and the ball bearings 36, operate as thrust elements and also as a means to support the sleeve 34 concentric of the shaft S. The peripheral portion of the sleeve 30 is provided with threads 37, and a second sleeve 38 is adapted to threadably engage about the sleeve 30, and is provided with interior threads engaging the exterior or peripheral threads 37. This sleeve 38 has fixed thereto adjacent the outer end, a ring 39 constituting a part of an anti-friction bearing or thrust element, and a second or inner ring 40 is secured about the hub 28, and each ring 39 and 40 is provided with a pair of confronting grooves in which are positioned anti-friction elements 41 in the form of ball bearings or the like. The antifriction bearing comprising the outer and inner races 39 and 40, respectively, and the ball bearings 41, hold the sleeve 38 concentric of the shaft S.

This anti-friction bearing also constitutes a thrust means whereby upon longitudinal movement of the sleeve 38 by rotation thereof about the threaded sleeve 30, the plate 27 carrying the expanding or contracting bars 24, will be moved longitudinally of the shaft S. A wheel 42, in the form of a gear, is secured about the sleeve 38, and an operating gear 43'meshes with the gear 42 and is adapted to be rotated by any suitable source so as to effect rotation of the gear 42 when it is desired to either expand or contract the sheave.

While we have disclosed a gear 42 secured to the sleeve 38, we do not wish to be limited to this particular construction, as other means may be used to rotate the threaded sleeve 38 when it is desired to either expand or contract the sheave so as to vary the speed of the drive or driven shaft.

In the use and operation of this device, the shaft S may be connected to a power means which is so mounted that upon expansion or contraction of the sheave hereinbefore described, the power means will move relative to the driven means either by sliding or rocking movement. In this manner, when the sheave is contracted, the space between the drive shaft and the driven shaft will accordingly be increased, and this can be appropriately taken up by shifting either the drive or the driven element.

When it is desired to enlarge the sheave hereinbefore described, the pinion or gear 43 may be rotated in the desired direction so as to rotate the wheel or gear 42 and likewise turn the threaded sleeve 38 so that the plate 27 with the rods 24 will be moved away from the fixed sleeve 30.

This movement will expand or force the segments 21 outwardly and thereby enlarge the circle of the sheave, and where the sheave is connected to a drive shaft, the speed of the driven element will thereby be proportionately increased, and where the sheave herein described is connected to the driven shaft or driven element, the sheave will be proportionately decreased.

It is, of course, understood that various changes and modifications may be made in the details of construction and design of the above specifically described embodiment of this invention without departing from the spirit thereof, such changes and modifications being restricted only by the scope of the following claims.

The circle described by the segments will be of a diameter intermediate the minimum and maximum diameters of the sheave so as to reduce the distortion due to the enlargement or reduction of the sheave.

What is claimed is:

1. An expansible sheave comprising a shaft, a hub structure on the shaft, a plurality of segmental sheave members, means for slidably mounting said members on the hub structure and operating means for moving said sheave members to enlarge or reduce the circle described thereby, said operating means comprising a pair of plates splined on said shaft, inclined bars connecting the plates together and engaging the mounting means for the sheave members, a sleeve fixed to one of said plates, an anti-friction race member secured to said fixed sleeve, a second sleeve having threads, 21 second anti-friction race member fixed to said second sleeve, anti-friction elements between said race members, a third sleeve having threads engageable with the threads of said second sleeve, a third anti-friction race member fixed to said shaft, a fourth anti-friction race member fixed to said third sleeve, anti-friction elements between said third and fourth sleeves, an arm fixed to said third sleeve, means engaging the arm for holding said third sleeve against rotary movement, and means for rotating said second sleeve to move said plates longitudinally of the shaft.

2. An expansible sheave, comprising a shaft, a hub structure on the shaft, segmental sheave members, means for slidably mounting said members on the hub structure, and operating means for moving said members to enlarge or reduce the circle described thereby, said operating means comprising a threaded sleeve loosely disposed about said shaft, means for holding said sleeve against rotation, a second sleeve threadably engaging said first sleeve, an operating member secured to said second sleeve, a third sleeve slidable on said shaft, means carried by said third sleeve engaging said mounting means for said segmental members to shift said segmental members relative to said hub structure upon movement of said third sleeve longitudinally on the shaft, and coacting means carried by said second and third sleeves whereby the same may have unitary movement longitudinally of the shaft while permitting rotation of one of said latter sleeves relative to the other and holding said latter sleeves against longitudinal movement relative to each other.

NOAH L. WHITTEN. ASA M. MOSELEY. 

